Method and means for surfacing roads



Aug. 8, 1933. J, N HELTZEL 1,921,185

METHOD AND MEANS FOR SURFACING ROADS Filed May 28, 1930 3 Sheets-Sheet 1JNHELTZEL/ l1g- 8*, 1933 J. N. HELTZEL ,92l,185

METHOD AND MEANS FOR SURFACING ROADS Filed May 28, 1950 3 Sheets-Sheet 2JNHELTEL] A05 3, 1933. J. N. HELTzEL 1,921,185

IETHQD AND MEANS FOR SURFACING ROADS Filed May 28. 1930 5 Sheets-Sheet 5N HELTZEL,

Patented Aug. 8, 1933 UNI-ET EDF' Si'I A T METHOD- AND-v MEANS. FORASURFACING R. ADS Y John N. Heltzel, Warren,A Ohio Application May 28,1930. Seriall No. 456,556

20 Claims.

The present invention relates to machines for use in building roads ofconcrete or the like and in operation upon the concrete when in aplastic state, and also for use in the surfacing of' road structures.

An object of the present invention is toprovide an improved jointproducing apparatus and method of operating the same, and to providenovel means and ways of finishing the concrete on opposite sides of thejoint which is produced.

Another object of the present invention is to provide an improved meansfor producing ay longitudinalY central joint in a roadway and means formaintaining the joint producing means in proper alignment with respectto the laterally disposed forms and without reference to any inequalitywhich may be inherent in the structure and incident to the operation ofthe carriage or frame of the machine.

The invention still further aims at the provision of an improved cutterand mounting therefor adapted for vertical adjustment from the frame orcarriage and which may be quickly and easily swung into and out ofposition for carrying on the various steps of the operation in formingand treating the plastic concrete surfacing structure.

Afurther object of the present invention `is to provide a novelconstruction of compacting tools or means for operation upon the surfaceof the roadway at opposite sides of the joint or seam which is formedand which may be operable immediately behind the blade or simultaneouslyat opposite sides thereof, and which is adjustable with reference to theblade ritself so as to at all times maintain the proper levelling of thesurface at opposite sides of the joint.

With the foregoing and other objects in view, which will be apparent asthe description proceeds, the invention resides Ain the construction andarrangement of parts as hereinafter described and claimed, it beingunderstood that changes can be made AWithin the scope of lwhat is`claimed, without departing from ythe spirit of 'the invention.

The invention is illustrated inthe accompanying drawings, wherein-Figure 1 isa fragmentary -perspective yview of a joint producingapparatus as Yapplied to the surfaceof aroadway, the dotted linesshowing the lforniingfblade -in raised-position out of the way.

Fig. '2 is a fragmentary enlarged transverse section through the forwardportion of vthe'a-ppa- 'lratus, showing the cutting =tool and :mountingtherefor as disposed with reference to the surface portion of theroadway and the side form therefor. v

Fig. 3 is a similar view butshowing a modified construction of cuttingimplement and guide`and mounting therefor.

Fig. 4 is a detail enlarged perspective View of a modified form ofcompacting implement or tool as applied to the formingfblade andl shownwith reference to the surface of the roadway.

Fig. 5 is a detail perspective ViewA of a further modified form ofcompacting implement or tool as applied tothe blade, and showing themethod of impressing aggregate into the surface of the Vroadway. atopposite sides of the joint.

Fig. 6 is a fragmentary perspective view showing in detail theadjustable mountingl of the forming blade partially removed from thejoint slot of the roadway, and showing a permanent joint strip mountedin a prior formed portion of the joint slot, and

Fig. 7 is a detail perspective view, enlarged, of one of the side formsfor the surface portion of the roadway and showing a guiding flangedWheel applied thereto.

Referring now to the drawings, and first-With particular reference toFigs. 1 and 2, 15 designates a plastic concrete slab in which is engageda cutting implement, such as the disk 16 mounted upon a transverselyextending shaft 17 mounted at opposite ends between pairs of rollers 18disposed in the lower ends of arms 19 which slidably fit through framemember 20 forming part of the carriage or frame of the main roadsurfacing machine. These arms 19 have handles 21 upon `their upper ends.by means of which the arms 19 may be raised and lowered so as toproperly adjust the cutting disk 16. The upper end portions of the .arms19 are provided with openings 22 therethrough adapted to receive pins orthe like for adjustably holding the arms 19 in vertically adjustedpositions through the frame .member 20. `One ofthe arms 19 may beprovided thereabout with a tension spring 23, shown in Fig; 2, whichis-adapted to Anormally urge the adjacent arm 19 downwardly .undersufficient pressure to hold a'gage wheel 24, `mounted on the adjacentendsof vthe ,shaft 17,-against the topof va side Arail or track 25 `eX-tending along Aone lateral portion of .the concrete slab 15. The armsupporting the cutting disc maybe provided withspringZS--A to transvmit`pressure to the. disc and will also .reliye ,the apparatus of strainscaused by ,the disc when rolling over steel dowel bars. v

The cutter 16 engages in the plastic mass and deflects to opposite sidesstones, and other large particles which are found in the mass and alsodivides the mass to provide a division slot 26 of the desired depth. Inorder to maintain, shape and preserve the slot in the desired size untilthe material has sufciently set, a shaping blade 27 is provided. Thisshaping or forming blade 27 is of desired length, is arranged verticallyin edgewise relation and in alignment with the disk 16, and ispreferably rounded downwardly and rearwardly at the forward end as shownto advantage in Fig. 1 so that the blade 27 may closely follow thecutting disk 15 and engage in the slot 26 so as to spread thewalls-thereof and maintain the walls in properly spaced apart relationuntil the plastic material sets sufl`1cient` ly to maintain the slot 26at the desired width and depth. In order to effect this relatively quicksetting of the material after the blade 27 has been inserted in the slot26, the plastic mass may have admixed therein the desired quantity ofcalcium chloride which produces a quick set in the concrete.

The forward end of the blade 27 is provided with an upstanding shank 28which is mounted by means of a pivot 29 upon the lower end of a standard30 which is suitably mounted upon the frame or carriage ofthe machine soas to maintain the blade 27 at the desired depth in the slot 26. It willbe noted that the shank 28 is of sufficientl length so that when theblade 27 is swung into raised position, as shown in dotted lines in Fig.1, the blade 27 will clear the upper surface portion of the slab l5 andwill permit of easy access to the opposite sides or edge portions of theslot 26 for subsequent treatment, such as compacting or the like. Tofacilitate the raising and lowering of the blade 27 the latter isprovided at its upper edge and near its rear end with a handle 31, andthe blade is also apertured adjacent to the handle for receivingtherethrough a pin 32 for connecting the handle to the lower end of anarm 33 which is vertically and slidably mounted in a portion of thecarriage frame 20, as clearly shown-in Fig. 1, the arm 33.beingadjustably held in position by means of a peg 34 adjustably engaging inopenings or the like formed in the arm 33 as shown.

The blade 27 is provided with an edging tool 35 in the form of arelatively flat plate adapted to extend across the slot 26 and overlapupon the plastic material at opposite sides of the slot, as shown inFig. 1. This edging tool 35 is provided with a depending web 36 whichmerges into the lower side of the plate 35 and is rounded at the pointof merging to conform with -the rounded configuration desired for theopposite upper edges of the slot 26. This plate 35 is carried upon therear end of an arm 37 which is pivotally mounted upon the pivot 32 nearthe forward end of the arm 37, and said forward end of the arm 37 isprovided with a threadedv eye 38 through which a threaded screw 39 iscarried, the lower end of the screw 39 abutting against said lug 40which projects from one side of the blade 27 so that by turning thescrew `39 downwardly the lower end of the arm 37 vis depressed. Theupper end of the screw 39 may be provided with suitable hand holds orthe like of any suitable configuration to facilitate the turning of thescrew 39. Thus the desired pressure of the edging tool may be obtainedby adjustment of the screw 39.

It may be found necessary in cases of unfavorable weather conditions,particularly during rainy weather, to protect the open joint or slot 26against damage, and to provide for this condition, a flexible strip 41which may comprise rubber or other suitable material, is mounted upon areel 42 carried by the frame 20 in such position that the strip 41 maybe payed out from the rear end portion of the ma chine as the lattermoves forwardly, the stripy 41 being of sufficient width to adequatelycover the slot 26, as shown in Fig. l. After the strip 41 has served itspurpose it may be reclaimed and rewound upon the spool 42 for subsequentuse. A rubber tubular member lil-A may be used in lieu of the strip 44.

The guide wheel 24 is provided with collars and set screws at oppositesides for securing the guide wheel upon the shafts 17, and the cuttingdisk 16 is also provided with collars and set screws, as shown in Fig.4, for securing the same in desired longitudinal relation upon the shaft17. The shaft' 17 is preferably made in two parts arranged intelescoping relation and adjustably secured together by means of a setscrew 43 so that the cutting disk 16 maybe disposed in properly spacedrelation from the guide wheel 24 dependent upon the width of the sectionof the slab 15 which is to be included between the y edge portion of theslab and the slot 25.

Referring now to Fig. 3, showing a modification of the guide member andthe cutting member disclosed in Fig. 2, a frame or supporting bar 44 iscarried transversely on the carriage or machine and is provided with apair of spaced socket members 45 and46 adjustably held upon the framemember 44 by set screws 47. The socket 46 receives therein the ball head48 of a guide member 49 of preferably hollow construction and providedwith spaced walls the lower ends of.y

which are free and unobstructed and adapted to engage over the upperflange of the side guide rail 25.- A channel iron 50 or the like iswelded or otherwise suitably secured between the sideI walls of theguide member 49 in spaced relation to the lower edge portions thereofand is adapted to seat flat upon the upper face of the rail 25 forholding the guide member 49 in proper position thereon. A spacing rod 51engages slid-A ably through the intermediate portion of the guide member49 and is adjustably held in xed relation thereto by means of a setscrew 52 threaded downwardly to the top of the guide member 49 as shownin Fig. 3. The spacing rodiv 51 extends transversely over the slab orupper surface of the roadway`15 andY its inner end is `slidablyconnected upon a cutting member 53. The cutting member 53 comprises arelatively flat plate adapted to move over the upper surface of the slab15 in desired spaced relation above the same and which is provided atits forward end with an upwardly inclined shank 54 terminating in a ballhead adapted for engagement in the socket 45. The plate 53 is providedwith a pair of upstanding flanges 55 having vertically disposed slots 56therein for the reception of the adjacent end of the spacing rod 51 andfor the purpose of permitting the rise and fall of the cutting member onthe rod 51. The rod 5l is provided at the outer sides of the iianges 55with stop collars 57 to hold the cutting` member against lateralmovement upon the rod 51. The under side of the plate 53 is providedv/itba depending vertically disposed vblade 58 which is curved upwardlyand forwardly at itsends and adapted to engage in the plastic mass forforn ing or cutting the groove therein. The blade 58 is adapted to takethe place of the disk 16 as shown in Fig. 2.

The plate 53 of the cutting member is provided at its rear end portionwith an upstanding lug 59 to which is pivotally connected the lower endof a connecting arm 60 having an eccentric strap 61 on its upper endencircling an eccentric 62 mounted upon a shaft 63 adapted to be turnedby the mechanism of the machine for raising and lowering the cuttingelement and vibrating the same so as tol insure a cutting action of theblade 58 in the plastic material. During operation of the eccentric 62the cutting element is thus raised and lowered at its rear end so as toinsure the proper cutting of the blade 58 through the material, theseparation of the npebbles and other particles contained in the plasticmass and the proper' formation of the groove 26.* The sockets 45 and 46provide for the transverse vibrations or shiftings of the main frame orcarriage of the machine without disturbing the relation between theguide member 49 and the cutting member 53.

ForV use in conjunction with the forming blade 27, there is shown inFig. 4 a novel construction of float. The float comprises `a pair ofspaced plates or boards 64 which are arranged horizontally at oppositesides of the blade 27 and are connected together by means oftransversely disposed brackets 65 which are of spring steel, providingmeans to open and close the blades, arched upwardly intermediate theirends so as to pass in spaced relation over the upper edge portion of theblade 27. The intermediate portions of the brackets 65 are provided withupstanding webs 66 which are connected together by an intermediate bar67 which provides a handle or connecting means by means of which thefloat may be operated or manipulated.

Each bracket 65 is providedat one side with a pair of verticallydisposed and vertically slotted ears 68 adapted to receive the .oppositeends of a roller 69Y therein. The ears 68 carry a vertically slidablebearing 70 therebetween, the bearing 70 extending across the upperportion of the roller 69 and engaging the opposite ends thereof for thepurpose of raising and lowering the roller 69 upon the verticaladjustment of the bearing 70 between the ears 68. Each bracket-65 isalso provided, at a point between and above the ears 68 with anoutstanding lug 7l through which is threaded an adjusting screw 72having a hand wheel or the like upon its upper end adapted to be turnedfor moving the bearing 70 downwardly and pressing the roller 69 againstthe upper edge portion of the blade 27. This adjustment provides for theeasy sliding movement of the float along the blade 27 and also admits ofthev vertical adjustment of the float with reference to the blade so asto properly even off the upper surfacer of the slab 15 at opposite sidesof the longitudinal slot 26.

`From Fig. 4 it will be noted that the inner edge of each board 64 isprovided with a de'- pending'tapering ange 73 adapted to engage in theupper portion of the groove 26 and to round oi the edge thereof to thedesired connguration. Also, the forward edges of the boardV 64 arebeveled or inclined and flare outwardly and forwardly with respect toeach other ras clearly shown in Fig. 4 and for the'purpose of .of thelongitudinally disposed blade 27.

Vsome of the earlier methods of installing mee Iso Both ends of 64 mayAbe' or, the carriage or frame of the machine may be brought to astandstill and the float operated lengthwise of the blade 27 while themachine is at rest. The forwardly outwardly flaring ends of the boards64 force the surplus plastic theoat is drawn lengthwise of the blade.

Referring now to Fig. 5,. there is shown a modification in theVconstruction of float ci presser for cooperation with the blade 2'7.kIn this instance, the device comprises a pair of rolls '74 which aremounted upon a transverse shaft 75 and positioned in spaced apartrelation for receiving the upper edge portion of the blade 27therebetween. The shaft 75 is provided, between the rolls 74, with asupporting or gauge roller 76 which is relatively small and adapted toride along the upper edge of the blade 27. The diameter of the gaugeroller 76 determines the extent to which the side rollers 74 project roodownwardly Vfrom the upper edge of the blade f 27 so las to engage theupper surface portion of the slab 15 while the latter is in asemi-plastic condition.

rEhe rollers 74 are operated on the ,opposite side In on both sides ofthe joint or slot 26. In Fig. 5 f

the coarse aggregate 77 is shown as being placed or spread along theupper' surface of the slab I5 against the opposite side of the blade 27and in position to be pressed by the rolls 74 into the surface portionof the plastic material. sufiicient quantity of this coarse aggregate 77has been delivered on eachside of the blade, the rollers 74 are broughtinto play to compact or depress the aggregate 77 and work the aggregateinto the plastic material to produce a sort of bond. It may be desirableto use a mechanical tamping method instead of the rollers 74, but

the latter are preferable because the product is even and smooth and therollers 74 may be manipulated at a inuch greater speed.

In Fig. 6 is illustrated the method of using the blade 27 when itisdesired to install premoided joints. The blade 27 is positioned in theconcrete slab l5, the blade being supported in L `position from thetraveling bridge or other portion of the carriage or frame by thedepending arm 19 at one end and the depending arm 33 at v its rear end.These arms 19 and 33, as disclosed in connection with Figs. l and 2, arevertically L.;

In some localities engineers kconsider After a concrete toward thelongitudinal blade 27- as adjustable so that the blade 27 may beadjusted to various heights. After the concrete has been compacted andfinished on each side of the blade 27, the blade is raised out ofposition by the hand grip 31, and is swung entirely clear of the slot26, as shown in dotted llines in Figpl. While the blade 27 is in thisraised position the vpremolded'or other suitably formed joint strip 78is inserted in the slot to be left permanently therein if desired. Thestrip 78 may be in the nature of a removable joint strip which later maybe removed and then the joint poured with suitable material. The strip78 serves to maintain the groove or slot in proper shape during thesetting of the material. The carriage or frame 20 is then moved forwardso that the free end of the blade 27 clears the forward end of the jointstrip-78 when the blade 27 is then moved down into the concrete eitherby gravity or by suitable forcing means which may be applied so that theblade 27 will extend down into the plastic mass to the desired depth.The

operation is repeated by compacting the material along the joint, and inthis method of operation the blade is notv drawn longitudinally throughthe plastic concrete.

Referring now to Fig. 7, there is'disclosed modified construction ofroad form or side rail which is disposed along one side of the plasticslab 15 to hold the same in form while setting. As shown, the formcomprises a lower road rail 79 having a relatively wide lower or basepor-- tion which extends outwardly and is adapted to seat on thesub-base to line and grade and staked in position by the stakes 80 whichextend downwardly through sockets 8l which are carried in diagonal braceplates 82 which extend between the outer upturned portionsV of the baseplate and the upper downturned edge of the rail 79. The lower rail 79 isprovided with a top rail 83 which is provided with a horizontal treadportion at its top and a depending web portion 84 at its inner edgeadapted to lap against the inner side of the rail 79 and slide thereonforV vertically adjusting 'the top rail 83.

Y A desired number of vertical supports in the `form of posts 85 aredisposed vertically through the top and bottom flanges of the lower rail79 and project downwardly into the sub-base of the roadway. The upperends of the posts 85 project beyond the top of the rail 79 and areadapted to engage beneath the tread portion of the upper rail 83 tosupport the Vsame in elevated position. Each post 85 is provided with avertical slot 86 which is arranged to extend above and below the upperportion of the rail 79 and which is adapted to receive therethrough awedge shaped key 87 which rests at its lower edge upon the upper surfaceportion of the lower rail 79 and which is adapted at its upper edge toengage the' upper end of the slot 86 so as to support the posts 85 atthe desired elevation and to thus support the top rail 83 at the desiredheight. The upper portionof the top rail 83 is of suitable width to holdand guide thereon the carriage wheel 88 which is mounted on the shaft 89of the frame or carriage.

It is of course understood that 'various changes and mcdiiications maybe made in the details of construction and design of the above speci.

cally described apparatus and also in the various steps of the methoddescribed in connection with the use of the apparatus without departingfrom the spirit of this invention, such changes and modifications beingrestricted only by the scope of the following claims.

Having thus described the invention, what is claimed as new is:

1. A joint producing apparatus, consisting of a movable frame over aplastic concrete surfacing structure, a longitudinal blade to be forcedinto the plastic concrete, the top of said blade projecting above thetop surface of the concrete, and means for finishing the concretemovable longitudinally on each` side of the blade independently of theblade.

2; A joint cutting and installing apparatus, consisting of a movablecarriage over the roadway under construction, a cutting blade suspendedfrom the carriage to separate the coarse aggregate in the line of thejoint, a joint producing blade to be dropped into the incision producedby the iirst named blade, and means for compacting and smoothing thematerial along the joint producing blade while the latterbladc is instationary position in the groove.

3. A methodl of producing joints in concrete roads, consisting ofpouring the concrete, subsequently slotting the concrete with a rigidblade, 10() supplying a quantity of stone or other suitable coarseaggregate longitudinally along each side `of the blade, compacting andworking the said gravel into the plastic concrete to produce a denserstructure and finishing the surface of the concrete on both sides of theblade, removing the blade from the groove and inserting joint materialin the groove.

4. A joint producing apparatus for a plastic concrete surfacingstructure, comprising a frame, a cutting member carried by the frame andadapted to engage in the plastic concrete surface for cutting a groovetherein, a forming bladey carried by said frame in rear of and in linewith said cutting member adapted to form and shape the groove afterbeing cut, and an edging device mounted upon the rear end of said bladeand arranged for adjustment with respect thereto for engaging the edgeportions of the groove formed by the cutting device and the l2() bladefor shaping and compacting the edge portions of the groove.

5. A joint -producing apparatusv of the character described, comprisinga frame, a cutting disk mounted in the forward end of the frame adaptedto engage in the upper surface of a plastic slabv for cutting a groovetherein, a blade mounted on said frame in rear of and in line with saidcutting disk, means lfor de. pressing said blade into the slot in saidslab formed by said cutting disk for shaping the slot, an adjustable'armmounted upon the rear end of said blade, means for adjusting said arm toraise and lower the rear end thereof, and a combined edging and pressingmember mounted upon the rear end of said arm adapted for engagement withthe edgeportions of said slot in the slab. 'Y

6. In joint producing apparatus for plastic concrete surfacingstructures, comprising a forming blade adapted to engage in the uppersurface of the concrete structure to form a slot therein, a pair` ofboards arranged at opposite `sides of said blade, brackets connectingsaid lengthwise of the blade and supported therefrom, and means carriedby the brackets and engaging the rollers for vertically adjusting thesame to raise and lower the boards with respect to the upper edgeportion of the blade.

7. A joint producing apparatus, a vertical arm, a forming bladepivotally mounted at its forward end to the lower end of said arm andadapted to be swung downwardly thereon for engagement in the uppersurface of a concrete structure for forming a slot therein, a secondvertical arm spaced rearwardly from said first arm, and means fordetachably securing the rear end portion of said blade to said secondarm for holding the blade at the desired depth in the concretestructure, said blade having a hand hold at its upper edge and adjacentits rear end portion for swinging said blade into and out of operativeposition.

8. A joint cutting and installing apparatus consistine of a carriagemovable over the roadway under construction, a blade onthe carriageadapted to be inserted in the concrete, and

means for compacting and smoothing the material along the blade whilethe blade is in stationary position in the concrete.

9. A joint cutting and installing apparatus consisting of a carriagemovable over the roadway under construction, a blade supported on acarriage adapted to penetrate the concrete, and means movable along` andguided by the blade While the latter is stationary for compacting andsmoothing the material at opposite sides of the blade.

1i). A joint cutting and installing apparatusv consisting of a carriagemovable over the roadway, a blade suspended from the carriage forpartially penetrating the concrete, and means lying on both sides ofsaid blade and having a rolling motion up and down upon the blade forcompactine' and smoothing the concrete material along the line of thejoint.

11. A joint cutting and installing apparatus consisting of a carriagemovable over the road- Way, a blade on the carriage for partiallypenetrating the concrete, means mounted to roll back and forth on saidblade and having portions extending on both sides of said blade forengaging the concrete to compact and smooth the same along the line ofthe joint, and adjusting means for varying the vertical position of saidlast named means.

12. The herein-described method for installing joints in plasticsurfacing structures, which consists in moving a blade in plasticconcrete, and smoothing the material along the line of the joint Whilethe blade is in position.

13. The herein-described method for producing joints in plasticsurfacing structures, which consists in moving the blade in plasticconcrete, and compacting and smoothing the surface of the concretematerial at opposite sides of said blade by motion back and forth guidedby the blade while the blade is in a stationary position.

14. The herein-described method for producing joints in plasticsurfacing structures which consists in initially cleaving the concrete,reforming the cleft, subsequently edging said cleft While smoothing theside surfaces of the same, and trailing protective strip in the cleft.

15. A joint cutting apparatus comprising a carriage, and concretecleaving means loosely connected to the carriage to permit the carriageto shift laterally Without imparting a like movement to the blade.

16. A joint cutting apparatus comprising a carriage, concrete cuttingmeans swivelly connected to the carriage, and guide means traveling onthe side form and also sWivelly connected to the carriage.

17. A joint cutting apparatus comprising a carriage, concrete cuttingmeans swivelly connected to the carriage and adjustable laterally of thecarriage, and guide means traveling on the side form swivelly connectedto the carriage and adjustable laterally of the carriage.

18. Thev method of forming joints in plastic concrete of a road underconstruction, consisting in pouring and surfacing the plastic material,containing coarse and ne aggregates, causing a separation of the coarseaggregate along the line of proposed joint to cause a zone of mortar toaccumulate, consisting of the finer aggregates, and thereafter moving amember in said zone and depositing additional coarse aggregates alongthe member and agitating the coarse and iine aggregate to cause amixture and bond of all material Within the zone to produce a densestructure along the zone of joint.

19. The method of forming joints in plastic concrete of a road underconstruction, consisting in pouring the concrete, containing ne andcoarse aggregate, and then moving a cleaving implement longitudinallyalong the line of a joint to separate the coarse aggregate along saidline to cause a zone of mortar to accumulate therealong, and thereafterpositioning a longitudinal blade in said mortar to form a groove, andthen applying suitable aggegate to said mortar to be mixed With saidmortar to absorb a portion of the mortar to create a denser structureand thereafter removing the blade to repeat the operation. f Y

20. The method of forming joints in plastic concrete of a road underconstruction, consisting in pouring and finishing the concrete,containing ne and coarse aggregate, then separating the coarse aggregatelongitudinally along the center ofthe road in line of ajoint kandcreating a zone of mortar along said line, then positioning alongitudinal blade in the mortar to form a groove, and applying coarseaggregate to be tamped into the mortar tol absorb a portion of themortar and produce a denser structure.

JOHN N. HELTZEL.

